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/11.2/sys/i386/i386/db_trace.c 308418 2016-11-07 12:10:17Z kib $");
   29 
   30 #include <sys/param.h>
   31 #include <sys/systm.h>
   32 #include <sys/kdb.h>
   33 #include <sys/proc.h>
   34 #include <sys/sysent.h>
   35 
   36 #include <machine/cpu.h>
   37 #include <machine/frame.h>
   38 #include <machine/md_var.h>
   39 #include <machine/pcb.h>
   40 #include <machine/reg.h>
   41 #include <machine/stack.h>
   42 
   43 #include <vm/vm.h>
   44 #include <vm/vm_param.h>
   45 #include <vm/pmap.h>
   46 
   47 #include <ddb/ddb.h>
   48 #include <ddb/db_access.h>
   49 #include <ddb/db_sym.h>
   50 #include <ddb/db_variables.h>
   51 
   52 static db_varfcn_t db_esp;
   53 static db_varfcn_t db_frame;
   54 static db_varfcn_t db_frame_seg;
   55 static db_varfcn_t db_gs;
   56 static db_varfcn_t db_ss;
   57 
   58 /*
   59  * Machine register set.
   60  */
   61 #define DB_OFFSET(x)    (db_expr_t *)offsetof(struct trapframe, x)
   62 struct db_variable db_regs[] = {
   63         { "cs",         DB_OFFSET(tf_cs),       db_frame_seg },
   64         { "ds",         DB_OFFSET(tf_ds),       db_frame_seg },
   65         { "es",         DB_OFFSET(tf_es),       db_frame_seg },
   66         { "fs",         DB_OFFSET(tf_fs),       db_frame_seg },
   67         { "gs",         NULL,                   db_gs },
   68         { "ss",         NULL,                   db_ss },
   69         { "eax",        DB_OFFSET(tf_eax),      db_frame },
   70         { "ecx",        DB_OFFSET(tf_ecx),      db_frame },
   71         { "edx",        DB_OFFSET(tf_edx),      db_frame },
   72         { "ebx",        DB_OFFSET(tf_ebx),      db_frame },
   73         { "esp",        NULL,                   db_esp },
   74         { "ebp",        DB_OFFSET(tf_ebp),      db_frame },
   75         { "esi",        DB_OFFSET(tf_esi),      db_frame },
   76         { "edi",        DB_OFFSET(tf_edi),      db_frame },
   77         { "eip",        DB_OFFSET(tf_eip),      db_frame },
   78         { "efl",        DB_OFFSET(tf_eflags),   db_frame },
   79 };
   80 struct db_variable *db_eregs = db_regs + nitems(db_regs);
   81 
   82 static __inline int
   83 get_esp(struct trapframe *tf)
   84 {
   85         return (TF_HAS_STACKREGS(tf) ? tf->tf_esp : (intptr_t)&tf->tf_esp);
   86 }
   87 
   88 static int
   89 db_frame(struct db_variable *vp, db_expr_t *valuep, int op)
   90 {
   91         int *reg;
   92 
   93         if (kdb_frame == NULL)
   94                 return (0);
   95 
   96         reg = (int *)((uintptr_t)kdb_frame + (db_expr_t)vp->valuep);
   97         if (op == DB_VAR_GET)
   98                 *valuep = *reg;
   99         else
  100                 *reg = *valuep;
  101         return (1);
  102 }
  103 
  104 static int
  105 db_frame_seg(struct db_variable *vp, db_expr_t *valuep, int op)
  106 {
  107         struct trapframe_vm86 *tfp;
  108         int off;
  109         uint16_t *reg;
  110 
  111         if (kdb_frame == NULL)
  112                 return (0);
  113 
  114         off = (intptr_t)vp->valuep;
  115         if (kdb_frame->tf_eflags & PSL_VM) {
  116                 tfp = (void *)kdb_frame;
  117                 switch ((intptr_t)vp->valuep) {
  118                 case (intptr_t)DB_OFFSET(tf_cs):
  119                         reg = (uint16_t *)&tfp->tf_cs;
  120                         break;
  121                 case (intptr_t)DB_OFFSET(tf_ds):
  122                         reg = (uint16_t *)&tfp->tf_vm86_ds;
  123                         break;
  124                 case (intptr_t)DB_OFFSET(tf_es):
  125                         reg = (uint16_t *)&tfp->tf_vm86_es;
  126                         break;
  127                 case (intptr_t)DB_OFFSET(tf_fs):
  128                         reg = (uint16_t *)&tfp->tf_vm86_fs;
  129                         break;
  130                 }
  131         } else
  132                 reg = (uint16_t *)((uintptr_t)kdb_frame + off);
  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 (TF_HAS_STACKREGS(kdb_frame))
  150                 kdb_frame->tf_esp = *valuep;
  151         return (1);
  152 }
  153 
  154 static int
  155 db_gs(struct db_variable *vp, db_expr_t *valuep, int op)
  156 {
  157         struct trapframe_vm86 *tfp;
  158 
  159         if (kdb_frame != NULL && kdb_frame->tf_eflags & PSL_VM) {
  160                 tfp = (void *)kdb_frame;
  161                 if (op == DB_VAR_GET)
  162                         *valuep = tfp->tf_vm86_gs;
  163                 else
  164                         tfp->tf_vm86_gs = *valuep;
  165                 return (1);
  166         }
  167         if (op == DB_VAR_GET)
  168                 *valuep = rgs();
  169         else
  170                 load_gs(*valuep);
  171         return (1);
  172 }
  173 
  174 static int
  175 db_ss(struct db_variable *vp, db_expr_t *valuep, int op)
  176 {
  177 
  178         if (kdb_frame == NULL)
  179                 return (0);
  180 
  181         if (op == DB_VAR_GET)
  182                 *valuep = TF_HAS_STACKREGS(kdb_frame) ? kdb_frame->tf_ss :
  183                     rss();
  184         else if (TF_HAS_STACKREGS(kdb_frame))
  185                 kdb_frame->tf_ss = *valuep;
  186         return (1);
  187 }
  188 
  189 #define NORMAL          0
  190 #define TRAP            1
  191 #define INTERRUPT       2
  192 #define SYSCALL         3
  193 #define DOUBLE_FAULT    4
  194 #define TRAP_INTERRUPT  5
  195 #define TRAP_TIMERINT   6
  196 
  197 static void db_nextframe(struct i386_frame **, db_addr_t *, struct thread *);
  198 static int db_numargs(struct i386_frame *);
  199 static void db_print_stack_entry(const char *, int, char **, int *, db_addr_t,
  200     void *);
  201 static void decode_syscall(int, struct thread *);
  202 
  203 static const char * watchtype_str(int type);
  204 int  i386_set_watch(int watchnum, unsigned int watchaddr, int size, int access,
  205                     struct dbreg *d);
  206 int  i386_clr_watch(int watchnum, struct dbreg *d);
  207 
  208 /*
  209  * Figure out how many arguments were passed into the frame at "fp".
  210  */
  211 static int
  212 db_numargs(fp)
  213         struct i386_frame *fp;
  214 {
  215         char   *argp;
  216         int     inst;
  217         int     args;
  218 
  219         argp = (char *)db_get_value((int)&fp->f_retaddr, 4, FALSE);
  220         /*
  221          * XXX etext is wrong for LKMs.  We should attempt to interpret
  222          * the instruction at the return address in all cases.  This
  223          * may require better fault handling.
  224          */
  225         if (argp < btext || argp >= etext) {
  226                 args = -1;
  227         } else {
  228 retry:
  229                 inst = db_get_value((int)argp, 4, FALSE);
  230                 if ((inst & 0xff) == 0x59)      /* popl %ecx */
  231                         args = 1;
  232                 else if ((inst & 0xffff) == 0xc483)     /* addl $Ibs, %esp */
  233                         args = ((inst >> 16) & 0xff) / 4;
  234                 else if ((inst & 0xf8ff) == 0xc089) {   /* movl %eax, %Reg */
  235                         argp += 2;
  236                         goto retry;
  237                 } else
  238                         args = -1;
  239         }
  240         return (args);
  241 }
  242 
  243 static void
  244 db_print_stack_entry(name, narg, argnp, argp, callpc, frame)
  245         const char *name;
  246         int narg;
  247         char **argnp;
  248         int *argp;
  249         db_addr_t callpc;
  250         void *frame;
  251 {
  252         int n = narg >= 0 ? narg : 5;
  253 
  254         db_printf("%s(", name);
  255         while (n) {
  256                 if (argnp)
  257                         db_printf("%s=", *argnp++);
  258                 db_printf("%r", db_get_value((int)argp, 4, FALSE));
  259                 argp++;
  260                 if (--n != 0)
  261                         db_printf(",");
  262         }
  263         if (narg < 0)
  264                 db_printf(",...");
  265         db_printf(") at ");
  266         db_printsym(callpc, DB_STGY_PROC);
  267         if (frame != NULL)
  268                 db_printf("/frame 0x%r", (register_t)frame);
  269         db_printf("\n");
  270 }
  271 
  272 static void
  273 decode_syscall(int number, struct thread *td)
  274 {
  275         struct proc *p;
  276         c_db_sym_t sym;
  277         db_expr_t diff;
  278         sy_call_t *f;
  279         const char *symname;
  280 
  281         db_printf(" (%d", number);
  282         p = (td != NULL) ? td->td_proc : NULL;
  283         if (p != NULL && 0 <= number && number < p->p_sysent->sv_size) {
  284                 f = p->p_sysent->sv_table[number].sy_call;
  285                 sym = db_search_symbol((db_addr_t)f, DB_STGY_ANY, &diff);
  286                 if (sym != DB_SYM_NULL && diff == 0) {
  287                         db_symbol_values(sym, &symname, NULL);
  288                         db_printf(", %s, %s", p->p_sysent->sv_name, symname);
  289                 }
  290         }
  291         db_printf(")");
  292 }
  293 
  294 /*
  295  * Figure out the next frame up in the call stack.
  296  */
  297 static void
  298 db_nextframe(struct i386_frame **fp, db_addr_t *ip, struct thread *td)
  299 {
  300         struct trapframe *tf;
  301         int frame_type;
  302         int eip, esp, ebp;
  303         db_expr_t offset;
  304         c_db_sym_t sym;
  305         const char *name;
  306 
  307         eip = db_get_value((int) &(*fp)->f_retaddr, 4, FALSE);
  308         ebp = db_get_value((int) &(*fp)->f_frame, 4, FALSE);
  309 
  310         /*
  311          * Figure out frame type.  We look at the address just before
  312          * the saved instruction pointer as the saved EIP is after the
  313          * call function, and if the function being called is marked as
  314          * dead (such as panic() at the end of dblfault_handler()), then
  315          * the instruction at the saved EIP will be part of a different
  316          * function (syscall() in this example) rather than the one that
  317          * actually made the call.
  318          */
  319         frame_type = NORMAL;
  320         sym = db_search_symbol(eip - 1, DB_STGY_ANY, &offset);
  321         db_symbol_values(sym, &name, NULL);
  322         if (name != NULL) {
  323                 if (strcmp(name, "calltrap") == 0 ||
  324                     strcmp(name, "fork_trampoline") == 0)
  325                         frame_type = TRAP;
  326                 else if (strncmp(name, "Xatpic_intr", 11) == 0 ||
  327                     strncmp(name, "Xapic_isr", 9) == 0)
  328                         frame_type = INTERRUPT;
  329                 else if (strcmp(name, "Xlcall_syscall") == 0 ||
  330                     strcmp(name, "Xint0x80_syscall") == 0)
  331                         frame_type = SYSCALL;
  332                 else if (strcmp(name, "dblfault_handler") == 0)
  333                         frame_type = DOUBLE_FAULT;
  334                 /* XXX: These are interrupts with trap frames. */
  335                 else if (strcmp(name, "Xtimerint") == 0)
  336                         frame_type = TRAP_TIMERINT;
  337                 else if (strcmp(name, "Xcpustop") == 0 ||
  338                     strcmp(name, "Xrendezvous") == 0 ||
  339                     strcmp(name, "Xipi_intr_bitmap_handler") == 0)
  340                         frame_type = TRAP_INTERRUPT;
  341         }
  342 
  343         /*
  344          * Normal frames need no special processing.
  345          */
  346         if (frame_type == NORMAL) {
  347                 *ip = (db_addr_t) eip;
  348                 *fp = (struct i386_frame *) ebp;
  349                 return;
  350         }
  351 
  352         db_print_stack_entry(name, 0, 0, 0, eip, &(*fp)->f_frame);
  353 
  354         /*
  355          * For a double fault, we have to snag the values from the
  356          * previous TSS since a double fault uses a task gate to
  357          * switch to a known good state.
  358          */
  359         if (frame_type == DOUBLE_FAULT) {
  360                 esp = PCPU_GET(common_tss.tss_esp);
  361                 eip = PCPU_GET(common_tss.tss_eip);
  362                 ebp = PCPU_GET(common_tss.tss_ebp);
  363                 db_printf(
  364                     "--- trap 0x17, eip = %#r, esp = %#r, ebp = %#r ---\n",
  365                     eip, esp, ebp);
  366                 *ip = (db_addr_t) eip;
  367                 *fp = (struct i386_frame *) ebp;
  368                 return;
  369         }
  370 
  371         /*
  372          * Point to base of trapframe which is just above the
  373          * current frame.
  374          */
  375         if (frame_type == INTERRUPT)
  376                 tf = (struct trapframe *)((int)*fp + 16);
  377         else if (frame_type == TRAP_INTERRUPT)
  378                 tf = (struct trapframe *)((int)*fp + 8);
  379         else
  380                 tf = (struct trapframe *)((int)*fp + 12);
  381 
  382         if (INKERNEL((int) tf)) {
  383                 esp = get_esp(tf);
  384                 eip = tf->tf_eip;
  385                 ebp = tf->tf_ebp;
  386                 switch (frame_type) {
  387                 case TRAP:
  388                         db_printf("--- trap %#r", tf->tf_trapno);
  389                         break;
  390                 case SYSCALL:
  391                         db_printf("--- syscall");
  392                         decode_syscall(tf->tf_eax, td);
  393                         break;
  394                 case TRAP_TIMERINT:
  395                 case TRAP_INTERRUPT:
  396                 case INTERRUPT:
  397                         db_printf("--- interrupt");
  398                         break;
  399                 default:
  400                         panic("The moon has moved again.");
  401                 }
  402                 db_printf(", eip = %#r, esp = %#r, ebp = %#r ---\n", eip,
  403                     esp, ebp);
  404         }
  405 
  406         *ip = (db_addr_t) eip;
  407         *fp = (struct i386_frame *) ebp;
  408 }
  409 
  410 static int
  411 db_backtrace(struct thread *td, struct trapframe *tf, struct i386_frame *frame,
  412     db_addr_t pc, register_t sp, int count)
  413 {
  414         struct i386_frame *actframe;
  415 #define MAXNARG 16
  416         char *argnames[MAXNARG], **argnp = NULL;
  417         const char *name;
  418         int *argp;
  419         db_expr_t offset;
  420         c_db_sym_t sym;
  421         int instr, narg;
  422         boolean_t first;
  423 
  424         if (db_segsize(tf) == 16) {
  425                 db_printf(
  426 "--- 16-bit%s, cs:eip = %#x:%#x, ss:esp = %#x:%#x, ebp = %#x, tf = %p ---\n",
  427                     (tf->tf_eflags & PSL_VM) ? " (vm86)" : "",
  428                     tf->tf_cs, tf->tf_eip,
  429                     TF_HAS_STACKREGS(tf) ? tf->tf_ss : rss(),
  430                     TF_HAS_STACKREGS(tf) ? tf->tf_esp : (intptr_t)&tf->tf_esp,
  431                     tf->tf_ebp, tf);
  432                 return (0);
  433         }
  434 
  435         /*
  436          * If an indirect call via an invalid pointer caused a trap,
  437          * %pc contains the invalid address while the return address
  438          * of the unlucky caller has been saved by CPU on the stack
  439          * just before the trap frame.  In this case, try to recover
  440          * the caller's address so that the first frame is assigned
  441          * to the right spot in the right function, for that is where
  442          * the failure actually happened.
  443          *
  444          * This trick depends on the fault address stashed in tf_err
  445          * by trap_fatal() before entering KDB.
  446          */
  447         if (kdb_frame && pc == kdb_frame->tf_err) {
  448                 /*
  449                  * Find where the trap frame actually ends.
  450                  * It won't contain tf_esp or tf_ss unless crossing rings.
  451                  */
  452                 if (TF_HAS_STACKREGS(kdb_frame))
  453                         instr = (int)(kdb_frame + 1);
  454                 else
  455                         instr = (int)&kdb_frame->tf_esp;
  456                 pc = db_get_value(instr, 4, FALSE);
  457         }
  458 
  459         if (count == -1)
  460                 count = 1024;
  461 
  462         first = TRUE;
  463         while (count-- && !db_pager_quit) {
  464                 sym = db_search_symbol(pc, DB_STGY_ANY, &offset);
  465                 db_symbol_values(sym, &name, NULL);
  466 
  467                 /*
  468                  * Attempt to determine a (possibly fake) frame that gives
  469                  * the caller's pc.  It may differ from `frame' if the
  470                  * current function never sets up a standard frame or hasn't
  471                  * set one up yet or has just discarded one.  The last two
  472                  * cases can be guessed fairly reliably for code generated
  473                  * by gcc.  The first case is too much trouble to handle in
  474                  * general because the amount of junk on the stack depends
  475                  * on the pc (the special handling of "calltrap", etc. in
  476                  * db_nextframe() works because the `next' pc is special).
  477                  */
  478                 actframe = frame;
  479                 if (first) {
  480                         first = FALSE;
  481                         if (sym == C_DB_SYM_NULL && sp != 0) {
  482                                 /*
  483                                  * If a symbol couldn't be found, we've probably
  484                                  * jumped to a bogus location, so try and use
  485                                  * the return address to find our caller.
  486                                  */
  487                                 db_print_stack_entry(name, 0, 0, 0, pc,
  488                                     NULL);
  489                                 pc = db_get_value(sp, 4, FALSE);
  490                                 if (db_search_symbol(pc, DB_STGY_PROC,
  491                                     &offset) == C_DB_SYM_NULL)
  492                                         break;
  493                                 continue;
  494                         } else if (tf != NULL) {
  495                                 instr = db_get_value(pc, 4, FALSE);
  496                                 if ((instr & 0xffffff) == 0x00e58955) {
  497                                         /* pushl %ebp; movl %esp, %ebp */
  498                                         actframe = (void *)(get_esp(tf) - 4);
  499                                 } else if ((instr & 0xffff) == 0x0000e589) {
  500                                         /* movl %esp, %ebp */
  501                                         actframe = (void *)get_esp(tf);
  502                                         if (tf->tf_ebp == 0) {
  503                                                 /* Fake frame better. */
  504                                                 frame = actframe;
  505                                         }
  506                                 } else if ((instr & 0xff) == 0x000000c3) {
  507                                         /* ret */
  508                                         actframe = (void *)(get_esp(tf) - 4);
  509                                 } else if (offset == 0) {
  510                                         /* Probably an assembler symbol. */
  511                                         actframe = (void *)(get_esp(tf) - 4);
  512                                 }
  513                         } else if (strcmp(name, "fork_trampoline") == 0) {
  514                                 /*
  515                                  * Don't try to walk back on a stack for a
  516                                  * process that hasn't actually been run yet.
  517                                  */
  518                                 db_print_stack_entry(name, 0, 0, 0, pc,
  519                                     actframe);
  520                                 break;
  521                         }
  522                 }
  523 
  524                 argp = &actframe->f_arg0;
  525                 narg = MAXNARG;
  526                 if (sym != NULL && db_sym_numargs(sym, &narg, argnames)) {
  527                         argnp = argnames;
  528                 } else {
  529                         narg = db_numargs(frame);
  530                 }
  531 
  532                 db_print_stack_entry(name, narg, argnp, argp, pc, actframe);
  533 
  534                 if (actframe != frame) {
  535                         /* `frame' belongs to caller. */
  536                         pc = (db_addr_t)
  537                             db_get_value((int)&actframe->f_retaddr, 4, FALSE);
  538                         continue;
  539                 }
  540 
  541                 db_nextframe(&frame, &pc, td);
  542 
  543                 if (INKERNEL((int)pc) && !INKERNEL((int) frame)) {
  544                         sym = db_search_symbol(pc, DB_STGY_ANY, &offset);
  545                         db_symbol_values(sym, &name, NULL);
  546                         db_print_stack_entry(name, 0, 0, 0, pc, frame);
  547                         break;
  548                 }
  549                 if (!INKERNEL((int) frame)) {
  550                         break;
  551                 }
  552         }
  553 
  554         return (0);
  555 }
  556 
  557 void
  558 db_trace_self(void)
  559 {
  560         struct i386_frame *frame;
  561         db_addr_t callpc;
  562         register_t ebp;
  563 
  564         __asm __volatile("movl %%ebp,%0" : "=r" (ebp));
  565         frame = (struct i386_frame *)ebp;
  566         callpc = (db_addr_t)db_get_value((int)&frame->f_retaddr, 4, FALSE);
  567         frame = frame->f_frame;
  568         db_backtrace(curthread, NULL, frame, callpc, 0, -1);
  569 }
  570 
  571 int
  572 db_trace_thread(struct thread *thr, int count)
  573 {
  574         struct pcb *ctx;
  575         struct trapframe *tf;
  576 
  577         ctx = kdb_thr_ctx(thr);
  578         tf = thr == kdb_thread ? kdb_frame : NULL;
  579         return (db_backtrace(thr, tf, (struct i386_frame *)ctx->pcb_ebp,
  580             ctx->pcb_eip, ctx->pcb_esp, count));
  581 }
  582 
  583 int
  584 i386_set_watch(watchnum, watchaddr, size, access, d)
  585         int watchnum;
  586         unsigned int watchaddr;
  587         int size;
  588         int access;
  589         struct dbreg *d;
  590 {
  591         int i, len;
  592 
  593         if (watchnum == -1) {
  594                 for (i = 0; i < 4; i++)
  595                         if (!DBREG_DR7_ENABLED(d->dr[7], i))
  596                                 break;
  597                 if (i < 4)
  598                         watchnum = i;
  599                 else
  600                         return (-1);
  601         }
  602 
  603         switch (access) {
  604         case DBREG_DR7_EXEC:
  605                 size = 1; /* size must be 1 for an execution breakpoint */
  606                 /* fall through */
  607         case DBREG_DR7_WRONLY:
  608         case DBREG_DR7_RDWR:
  609                 break;
  610         default:
  611                 return (-1);
  612         }
  613 
  614         /*
  615          * we can watch a 1, 2, or 4 byte sized location
  616          */
  617         switch (size) {
  618         case 1:
  619                 len = DBREG_DR7_LEN_1;
  620                 break;
  621         case 2:
  622                 len = DBREG_DR7_LEN_2;
  623                 break;
  624         case 4:
  625                 len = DBREG_DR7_LEN_4;
  626                 break;
  627         default:
  628                 return (-1);
  629         }
  630 
  631         /* clear the bits we are about to affect */
  632         d->dr[7] &= ~DBREG_DR7_MASK(watchnum);
  633 
  634         /* set drN register to the address, N=watchnum */
  635         DBREG_DRX(d, watchnum) = watchaddr;
  636 
  637         /* enable the watchpoint */
  638         d->dr[7] |= DBREG_DR7_SET(watchnum, len, access,
  639             DBREG_DR7_GLOBAL_ENABLE);
  640 
  641         return (watchnum);
  642 }
  643 
  644 
  645 int
  646 i386_clr_watch(watchnum, d)
  647         int watchnum;
  648         struct dbreg *d;
  649 {
  650 
  651         if (watchnum < 0 || watchnum >= 4)
  652                 return (-1);
  653 
  654         d->dr[7] &= ~DBREG_DR7_MASK(watchnum);
  655         DBREG_DRX(d, watchnum) = 0;
  656 
  657         return (0);
  658 }
  659 
  660 
  661 int
  662 db_md_set_watchpoint(addr, size)
  663         db_expr_t addr;
  664         db_expr_t size;
  665 {
  666         struct dbreg d;
  667         int avail, i, wsize;
  668 
  669         fill_dbregs(NULL, &d);
  670 
  671         avail = 0;
  672         for(i = 0; i < 4; i++) {
  673                 if (!DBREG_DR7_ENABLED(d.dr[7], i))
  674                         avail++;
  675         }
  676 
  677         if (avail * 4 < size)
  678                 return (-1);
  679 
  680         for (i = 0; i < 4 && (size > 0); i++) {
  681                 if (!DBREG_DR7_ENABLED(d.dr[7], i)) {
  682                         if (size > 2)
  683                                 wsize = 4;
  684                         else
  685                                 wsize = size;
  686                         i386_set_watch(i, addr, wsize,
  687                                        DBREG_DR7_WRONLY, &d);
  688                         addr += wsize;
  689                         size -= wsize;
  690                 }
  691         }
  692 
  693         set_dbregs(NULL, &d);
  694 
  695         return(0);
  696 }
  697 
  698 
  699 int
  700 db_md_clr_watchpoint(addr, size)
  701         db_expr_t addr;
  702         db_expr_t size;
  703 {
  704         struct dbreg d;
  705         int i;
  706 
  707         fill_dbregs(NULL, &d);
  708 
  709         for(i = 0; i < 4; i++) {
  710                 if (DBREG_DR7_ENABLED(d.dr[7], i)) {
  711                         if ((DBREG_DRX((&d), i) >= addr) &&
  712                             (DBREG_DRX((&d), i) < addr+size))
  713                                 i386_clr_watch(i, &d);
  714 
  715                 }
  716         }
  717 
  718         set_dbregs(NULL, &d);
  719 
  720         return(0);
  721 }
  722 
  723 
  724 static const char *
  725 watchtype_str(type)
  726         int type;
  727 {
  728         switch (type) {
  729                 case DBREG_DR7_EXEC   : return "execute";    break;
  730                 case DBREG_DR7_RDWR   : return "read/write"; break;
  731                 case DBREG_DR7_WRONLY : return "write";      break;
  732                 default               : return "invalid";    break;
  733         }
  734 }
  735 
  736 
  737 void
  738 db_md_list_watchpoints()
  739 {
  740         struct dbreg d;
  741         int i, len, type;
  742 
  743         fill_dbregs(NULL, &d);
  744 
  745         db_printf("\nhardware watchpoints:\n");
  746         db_printf("  watch    status        type  len     address\n");
  747         db_printf("  -----  --------  ----------  ---  ----------\n");
  748         for (i = 0; i < 4; i++) {
  749                 if (DBREG_DR7_ENABLED(d.dr[7], i)) {
  750                         type = DBREG_DR7_ACCESS(d.dr[7], i);
  751                         len = DBREG_DR7_LEN(d.dr[7], i);
  752                         db_printf("  %-5d  %-8s  %10s  %3d  ",
  753                             i, "enabled", watchtype_str(type), len + 1);
  754                         db_printsym((db_addr_t)DBREG_DRX((&d), i), DB_STGY_ANY);
  755                         db_printf("\n");
  756                 } else {
  757                         db_printf("  %-5d  disabled\n", i);
  758                 }
  759         }
  760 
  761         db_printf("\ndebug register values:\n");
  762         for (i = 0; i < 8; i++) {
  763                 db_printf("  dr%d 0x%08x\n", i, DBREG_DRX((&d), i));
  764         }
  765         db_printf("\n");
  766 }
  767 
  768 

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